For many years chlorine has been widely used to disinfect water and sewage. Customarily, liquid chlorine is converted to chlorine gas which is then introduced into the stream of water or sewage through a gas injector. Bromine chloride has recently been promoted for similar use, but the mixing of liquid bromine chloride with water in lines away from the main water or sewage stream produced plugging of these lines. Furthermore, flashing or instantaneous evaporation of the liquid bromine chloride in the metering pumps resulted in the stoppage of flow from these pumps. As an additional problem, the introduction of bromine chloride as a gas into the liquid stream to be treated required expensive evaporation equipment and gas injection apparatus.